Process for the sealing of cracks in the lining of blast furnaces and the like



' incense.

THOMAS KENNAN, BIRMINGHADI, ALABAMA.

PROCESS FOR THE SEALING OF CRACKS -ments in Process forthe Sealing of Cracks in the Lining of Blast Furnaces and the 1 like, of which the following is a specification. i v

This invention relates to a process for the sealing of cracks in the lining of blast furnaces andthe like, and has for its ob- .ject' to'enable the blast furnace operator to seal or close up cracksiin the furnace-lining -without having to shut down and reline .the furnace. e

, Due to the uneven expansion and ,con-' traction between the lining and shell of the I furnace and to other causes, cracks from time to time occur in: the liningof blast furnaces and heretofore the practice has been to shut down the furnace and reline it.

'Many processes have been tried experimentally to seal or close these cracks with out shutting down the furnaceor relining it, but so far as I am advised none heretofore have proven practical and successful.

According to the practice of my process, which I will now describe in manner and form sufliciently clear for those skilled in the art to practice it, when a crack occurs in the furnace lining it is indicated by the metallic jacket opposite the crack becoming red hot and when this occurs I am able to locate and define the extent of the crack. If this occurs in the lining above the bosh and below the down-comer pipe, my process will correct it, but if occurring above the bottom level of the down-comer my process will not correct it.

Assuming that a crack has occurred within the zone first described of the furnace lining, I provide as follows. First I prefer to tap out of the furnace all of the molten iron and slag, but this is not essential except to protect the grade of the molten iron. I then, if such step is necessary, introduce stock sufiicient to bring the stock line well above the level of the crack. The blast is then cut off and one or more tuyeres in vertical alignment with the zone of the crack are removed. I preferably then close off all of the other tuyeres so that air can gain admission to the furnace only through IN THE LINING OF BLAST FU LIKE. i

RNACES AND THE the tuyere ports under the crack. By this means I cause -a1r' drawn in'by the natural draft of the furnace to flowin through the open tuyere port or ports and to creep up along the furnace lining and passing over the zone of thec'rack. This being the only zone and as this melted stock flows down the furnace lining and over the crack it, will enter the latter responsiveto capillary attraction'and will fill and seal the crack. By raising and lowering the bell the intensity of the draft can be controlled and all of the metallic parts of the furnace properly protected. v

The removal of the tuyeres under the crack is the simplest way of concentratingv the flow of airso that it will pass up along the lining over the cracked zone, as when the tuyeres are left in place with the blast onthey will tend to direct the air towards the center of the furnace andvto keep it away from the lining. q i i The principle underlying my invention is to so control and direct the air that it will cause the melting of thestock opposite and above the cracked zone,1and obviously my invention in its simplest form is carried out when this melting is localized opposite the zone of the crack, as by localizing it I increase the intensity of the draft for the more effective melting of the stock in the zone desired. V

While I have described above, as a preferred method for accomplishing this, the

opening of the tuyere ports under the crack and the shutting off of the blast through the other tuyeres, nevertheless, under certainconditions, approximately the'same effect can be obtained where the blast is shut off from the tuyeres under the cracked zone and is left on in one or more tuyeres diametrically opposite to the cracked zone, as

in this way the open tuyeres maybe able to direct the air across the bosh and cause it to flow u along the opposite wall and over the cracked zone. Also, as a modification of my method, all of the tuyeres can be removed and the bell lowered, thereby increasing the draft of air flowing up along Specification of Lettersratent. Patented July 18, 1922.

Application filed January 14, 1922. Serial N01 529,340.'

the lining on all sides and melting down the stock all around and continuing this until the crack is sealed. Obviously, quicker and better results are obtained where the draft is concentrated on the stock opposite the cracked zone.

In the accompanying my preferred process in use. Here the furnace comprises an outer metallic jacket 1, a lining 2, a bosh 3, tuyere ports f for t'uycres not shown which are connected to the bustle pipe 5. The down-comer pipe (3 leads from the top of the furnace adjacent to the hell 7. I show a crack 8- in the furnace lining and the stock 9 is represented at a level above the crack, The tuyere ports in vertical alignment with the crack are shown open and plugs 10 are shown inserted in the other tuyere ports. I show by arrows the inflow of air and it will be seen passing up along the lining and over thecracked zone; This will cause a rapid melting of the stockwhich will flow down the furnace and over the cracked zone and willseal the crack without requiring the furnace to be shut down.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is

1. The hereindescribed process for the sealing of cracks in the lining of blast furnaces and the like, which consists in raising the stock level above the cracked zone and concentrating a flow of air through the stock adjacent to and above the cracked zone to cause the same to melt and run down the furnace lining and enter the crack.

2. The hereindescribed process for the drawing I have illustra-ted a typlcal blast furnace showing crack.

sealing of cracks in the lining of blast furnaces and the like, which consists in shutting off the blast, raising the stock level It when necessary above the cracked zone, re-

moving one or more tuyeres in vertical alignment with the cracked zone, and preventing the access of air through the other tuyeres so as to cause a draft to flow through the open tuyere ports up along the furnace lining and over the cracked zone.

3. The hereindescribed process for the sealing of cracks in the lining of blast furnaces, which consists in the raising when necessary of the stock level above the cracked zone, and the arranging of the air admission elements so as to cause the air entering the bosh to flow up along the lining of the furnace and to melt down the stock contiguous to the lining so that it will tend to flow down the lining and enter the 4. The hereindescribed process for the sealing of cracks in the lining of blast furnaces, which consists in the raising when necessary of the stock level above the cracked zone, and'the arranging of the air admission elements so as to cause the air entering the bosh to flow up along the lining of the furnace and to melt down the stock contiguous to the lining so that it will tend toflow down the lining and enter the crack, and controlling the'draft by the raising and lowering of the bell.

In testimony whereof I affix my signature.

THOMAS KENNAN.

Vitness:

ilonni WELSH. 

